Trammel



J. W. THEIN Sept. 2, 1952 TRAMMEL Filed Jan. 2, 1948 FlE.Z

FIEJ.

- INVENTOR. JOHN W THEIN includes a cylindrical shank 19 having a threaded end 20 of reduced diameter designed to be threaded into the aperture 16. An axial socket 2! is provided in the outer end of this shank. A second shank 22 is provided with a threaded end 23 of proper size to fit into the socket 21. The shank 22 is provided with a pointed outer end 24 which may be of hard metal to serve as a scratch point if it is so desired.

In place of the threaded shank end 29, this end of the shank may extend through the aperture l6 and be riveted in place if it is so desired.

The threaded construction illustrated is advantageous as the shank may be removed from the U-shaped member H when desired to remove or replace the spring member. The formation of the pointed end of the marking device in two parts is advantageous as the pointed end portion 24 may be of extremely hard material if desired to serve as a marking point. Furthermore, this construction permits the point to be replaced without replacing the entire shank.

A U-shaped spring 25 is provided on the marking device B. This spring 25 is curved to a larger radius than the curved portion ll of the U- shaped bracket II. The central portion of the U-shaped spring 25 is apertured to fit the small diameter portion 16 of the shank l9 and the spring is clamped between the large diameter portion of the shank and the curved end H of the U-shaped bracketg'Tlie opposite ends 26 and 21 of the spring are provided with apertures 29 and 30 therein. Each aperture is provided with converging edges 3| directed toward the adjacent end of the spring anda rounded side 32 opposite these converging edges. The apertures 29 and 30 are of sufiicient size to freely accommodate the beam in and to allow the spring to flex considerably while the beam extends through the apertures.

In inserting each marking device B onto the beam 10 the ends 29 and 2] of the spring 25 are flexed together under spring tension until the apertures'29 and 30 are aligned with the apertures l2 and I3 of the support ii. The beam l9 may then be inserted through, these aligned apertures. While the marking device B is being moved along the beam ID, the ends of the spring are preferably flexed into the position illustrated in dotted outline in Figure l of the drawings, at which time all of the walls of the apertures 29 and 30 are free of the beam in so that the marking device may slide freely thereupon. When it is desired to lock the marking device in any adjusted position upon the beam, it is only necessary to release the pressure upon the spring ends 26 and 21, allowing these spring ends to flex outwardly and engage the beam [9 under spring tension. The spring 25 tends to straighten out or to assume a curve of substantially larger radius than is possible while the marking device is engaged on the beam so that the pointed ends or diverging walls 3| of the apertures 29 and 30 engage the beam under spring tension. As a result the beam is clamped against the inner walls of the apertures 12 and i3 through the support H and the marking device is firmly held from longitudinal movement.

In Figure 4 of the drawings I disclose a modifled form of marking device indicated in general by the numeral C. This device C includes a U-shaped support 33 which is identical in construction to the support II previously described. The pointed end of the instrument includes an elongated shank .34 having a threaded end 35 of reduced diameters. The stem; end 3'5 extends through an aperture in the closed end of the The U *shaped spring 36, identical to the spring 2! previously described, is clamped between the larger diameter portion of the shank 34 and the rounded end of the support 33. The shank 34 is provided with a pointed end 31 which may be used for marking or measuring purposes.

In Figures 5' and 6 of the "drawings I disclose a marking-device D which is similar in some respects to the marking devices previously described. The marking device D includes a U-shaped support 39 which is identical to the support H and which is provided with aligned apertures 40 and 4| in opposite sides thereof.

An elongated sleeve 42 having a closed end 43 is secured to the rounded end of the support 39.. A threaded shank 44 projects axially from the: closed end 43 of the sleeve 42 and a spring 45'; identical to the spring 25 previously described is: clamped between the closed sleeve end 43 and the: rounded end of the U-shaped support 39, the: threaded shank 44 extending through a suitable.- aperture 46 in the support.

A leaf spring .41 is secured to the sleeve 42' near the center thereof. by rivets 49 or other suitable attaching means. This spring 41 is provided with an inturned "end 50 which extends through a transverseslot 5| near the open end of the sleeve 42.. This spring end 50 is designed to engage against: a piece of chalk 52, a crayon, or some other suitable marking. means preferably having a pointed ou'ter-end'53. This spring end 50 bears against or-digs into the chalk, or marking device to prevent accidental longitudinal movement thereof. By flexing the spring 41 cut- Wardly the chalk or crayon maybe moved outwardly of the sleeve. F

This marking device D mat be substituted for either or both of the marking means B illustrated in Figure 1 of the drawings. If the device is to be used as a beam compass, it is possible to substitute one. marking device D for one of the marking devices B and to use the pointed metal marking device B asthe center of the circle and the chalk or crayon as'the marking means to definea circle. I

In accordance with the patent statutes, I have described the principles of construction and operation ofmy trammeLlT and whileI have endeavored to set forth the best embodiments thereof, I desire to have it understood that obvious changes may be made within the scope of the following claimwithout' departing from the spirit of my invention. l

I claim:

A trammel comprising an elongated beam, a relatively rigid U-shaped'bracket slidably supported on said beam, said bracket having spaced sides and a connecting base, said sides being provided with apertures spaced suiiiciently from the free ends thereof to provide finger gripping por tions on said sides, said apertures in the sides of said bracket fitting about said Ibeam with a. sliding fit; arelatively flexible U.-shaped spring slidably supported on said beam, said spring having spaced sides and a connecting base which is fixedly anchored to the connecting base of said bracket, said spring sides beingfprovided with apertures spaced sufliciently from the free ends thereof to provide finger-gripping portions commensurate in length" with'thefingergripping portions on said bracket sides, said apertures in the sides of said spring'being relatively large to permit movement of the beam therethrough when said spring is flexed, said spring normally being biased against said beam on opposite sides of said bracket to hold said bracket from movement on said beam, whereby the person using the trammel is provided with a choice of gripping the finger portions of either bracket side and the finger portion of the next adjacent spring side or gripping the finger portions of both spring sides.

JOHN W. THEIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

